GEOEFFECTIVE. “The Sun affects the Earth and its environs in a variety of ways and on many different timescales. Events on the Sun leading to large perturbations in the coupled magnetosphere-ionosphere system are called geoeffective. From space weather point of view the key question is how to distinguish those solar events that are geoeffective from those that are not.”
https://link.springer.com/article/10.12942/lrsp-2007-1